Web guide



Jan. 27, 1959 F. J. MARKEY WEB GUIDE Filed April 3, 1956 2,871,013Patented Jan. 27, 1959 WEB GUIDE Frank J. Markey, Hammond, Ind.,assignor to GPE Controls, Inc., Chicago, 111., a corporation of IllinoisApplication April 3, 1956, Serial No. 575,808 12 Claims. (Cl. 271-26 Thepresent invention relates to detection of the lateral positions of theedges of longitudinally traveling webs, and to web guiding, wherein thetransverse position of a longitudinally traveling web is maintained inpreselected relation to apparatus to or from which the web is being fed,by relative transverse shifting of the apparatus and web to correctdepartures from the correct, preselected transverse positional relation.

. More particularly, the invention relates to that general type of webedge position detecting and indicating, and web guiding, in situationswherein the web is of varying width. Heretofore quite satisfactoryapparatus has been developed for use with webs of regular or onlyslightly varying widths operating by detection of the lateral positionof a single web edge. In situations wherein the web width may vary toany substantial extent, such a single edge-detectingdevice may be whollyunsatisfactory. The

present invention is based on the concept of detecting and indicatingthe position of the transverse center line of the web,and, in guiding,it is extended to embrace maintenance of the web center line in apreselected path by automatically shifting the web, or, in case the webis being fed to or from apparatus that performs some operation upon it,relatively shifting the apparatus and web, to correct variance of theweb center line from its preselected path or to correct variance fromthe proper transverse positional relation between theweb and apparatus.

This mode of operation is accomplished by continuously detecting thelateral positions of both of the web edges, and developing detectorsignals the magnitudes of which vary continuously and proportionallywith distances of lateral change in the positions of the web edges, Bythis type of detection and signal development, the magnitudes of thedetector signals afiord continuous indication of the distances by whichthe different web edges are spaced from a preselected reference pointbetween and from which the detectorsare symmetrically spaced.Consequently it has capacity for detecting asymmetric spacing of the twoweb edges fromthe reference point, whether it be caused by lateral shiftof the web, or by change of the position of one or both web edgeswithout lateral shift of the web as a whole, the latter being aconsequence of an asymmetric variation in the web width. On the otherhand, if a change in web width is symmetrical, the magnitudes of thedetector signals will change equally. This type of detection affords thepossibility of direct and continuous automatic comparison of thedetector signal magnitudes, and from them developing a resultant signalof which the magnitude represents degree of. unequal spacings of thedifferent web edges from the intermediate reference point, or variancefrom theweb. centerline from its preselected path, and consequently thesignal may be used either for indicating purposes alone, or as a controlsignal to actuate servo mechanism arranged to reestablish the web centerline in its correct path. 7. t

Heretofore, certain web guiding equipment has embodied paired webedgedetectors respectively disposed variation of web edge lateralpositionrepresenting signals,

comparison of which serves to indicate presence and degree of varianceof the two web edges from symmetric spacing from an intermediatereference point in a preselected location.

. In the accompanying drawings:

Fig. 1 is a somewhat schematic plan of a web guiding system embodyingthe invention.

Fig. 2 is an enlarged section on line 22 of Fig. 1.

In the arrangement shown in Fig. 1, the apparatus to which a web 6 isfed longitudinally, from a supply roll 7, and which apparatus performsan operation on the web, is shown as a slitter 8, comprising. one ormore rotary knives such as shown at 9 mounted on a power shaft 10 insuitable number and spacing to perform the required division of web 6.Shaft 10 is mounted on stationary bearing assemblies 11. In thearrangement shown, roll 7 is supported on a suitable carriage 13arrangedfor adjusting movement in directions extended transverse to the web 6,for example by elongate slots 14 wherein station ary guide pins 15 areslidably engaged. A power unit 16 is provided for moving base 13 androll-,7, forthe purpose of transversely positioning web 6, that is, fortransverse adjustmentwof its path to apparatus 8, unit 16 being shown asa hydraulic piston and cylinder assembly. Operation of unit 16 iscontrolled by. a hydraulic relay regulator 17, having a control elementthat is movable from a neutral position wherein unit 16 is maintainedout of operation, in opposite directions respectively to operate unit 16in reverse directions, thereby to accomplish adjustment in oppositedirectional senses of the transverse relation between the feed path ofweb 6 and apparatus 8.

Regulator 17 is shown as a conventional jet pipe device of which themovable control element 18 comprises a pipe that is pivoted for swingingabout an axis 19, and that has an end orifice at 24) for discharging athigh velocity an axial stream or jet of pressurized liquid delivered toit through a supply connection 21. According to the angular position ofthe jet pipe, its discharge orifice registers more or less with thedifferent ones of a pair of receiver ports 22 that are closely spaced inthe directions of its swing path, and which respectively are connectedto the different ends of the cylinder 23 of power unit 16. In theneutral position of member 18, discharge orifice 20 is in equalregistration with ports 22, so that equal pressures are developed in therespective ends of the cylinder 23, but upon swinging of member 18 fromits neutral position, unequal registration of the discharge orifice withthe different ports 22 results in development of a pressuredifferential. acrossthe piston 24 of the power unit 16,- resulting inoperation of unit 16 to shift. carriage 13 and roll 7, therebytransversely shifting web 6 and accomplishing the relative adjustment ofthe web path and apparatus 8.

r Web 6 is shown exaggeratedly as having irregularly varying width, dueto irregular edges 25, 26. The present invention is directed primarilyto the problem of maintaining the center line, indicated at; 27, of sucha web in a preselected path having a preselected transverse positionalrelation to apparatus such as slitter 8. Inherently apparatus embodyingthe inventionwill operate to correct the transverse shifting thatnormally occurs in web feeding, irrespective of regularity orirregularity of Web-width, such as maybe caused, for example, bytelescopic formation of the supply roll, lateral inequality in tension,and so on.

In accordance with the invention, a pair of web edge lateral positiondetectors 29, 30 aremounted in fixed tinuously and proportionally inresponse to variation in the-lateral positions of the web edges 25, 26which respectivelythe detectors'are positioned to sense. Preferably thedetectors 20, 30 are of the type shown in Fig. 2, comprising a deliverystructure 34 and a receiver structure 35, which are spaced apartinopposed, facing relation to provide between them-a throat 36 forpassage ofthe marginal portion of the web. Structure 34'is provided witha nozzle slot 37 for discharge of a sheet-like jet of air thelength-ofwhich-is extended transverse to the' web edge that it senses, andstructure 35 with a receiver slot 38 registered with nozzle slot 37across throat 36, for reception of so much of the air jet as isunintercepted by the marginal portion ofthe web, whereby themagnitudeofpressure developed in an internal chamber 39 of receiverstructure 37 varies as a function of the lateral position ofthewebedgeand continuously corresponds to that position. That pressure magnitude,which is used asa signal, also represents the spacing of the web edgefrom any preselected reference point spaced from the detectortransversely of the web andinwardfrorn the location of the detector, andconsequently-may be considered as indicating'the 'spacing of the webedge from a reference line that-has been selectedas the correct path tobe followed by'the center line of the web as it travels to theapparatus. Since detectors 29, 30 respectively are disposed to sense thelateral positions-of the ditferent web edges 26, 27, or,

as indicated, the-distances that those different web edgesare spacedfrom a line preselected as the correct path for the web center line,comparison of the positions or distances-represented by the signalsdevelopedby the respective detectors will indicate existence, sense andmagnitude of differences in those spacings. In accordance-with theinvention, these spacing distances are automatically and continuouslycompared, and from them is developed an indicating or control signalthat continuously and proportionally corresponds to the relationship ofthe distances spacing the different web edges from the preselectedcenter line path.

Conveniently a translating device may be arranged to perform thiscomparison function and to set the control element 18 in correspondanceto the resultant. The fluid pressure signal detecting system describedabove particularly' lends itself to this type of arrangement. In theillustrated system, the translator device comprises a force balanceassembly, generally. designated 41. It comprises a pair of expansiblechamber devices, shown as diaphragm assemblies 42, 43, the chambers ofthe different ones of which are connected respectively to the receiverstructure signal pressure chambers 39 of detectors 29, 30 by signalpipes 4-4. The diaphragms d5, d6 of assemblies 42, 43 are mechanicallylinked to control element 18 to exert oppositely thereon the forcesdeveloped by the diaphragms, which forces correspond to the signalpressures developed by the detectors 29, 3t and respectively exerted inthe chambers of assemblies 42, 43. Centering springs 47 maybe provided.

It is unavoidable in a system of the kind disclosed that response of twodetector-translator systems, such as 29, d2, 45- and 3t), 43, 46 will bedifferent, that is, output force changes by the two-systems in responseto" equal lnteral changes in web edge'positio'ns will be of ditferentmagnitudes. One of the principal advantages of a jet pipe regulator,particularly in web guide applications, is extreme sensitivity to signalforce variations, and rapidity of response of the power unit. These twofactors necessitate, in the system of Fig. 1, provision of readilyadjustable means for compensating response differences of the twodetector-translator systems that detect and compare the positions of thetwo web edges, to provide indication of difierences in their spacingsfrom an intermediate reference point, and development of a. signal themagnitude and sense of which correspond" respectively todegree anddirection of displacements of the web center line from a preselectedpath having a definite transverse positional relation to apparatus to orfrom which the Web is being fed.

Such means is shown in the form of a so-called ratioslider assembly 51.This assembly comprises a lever 52 interposed in the linkage mechanismfor transferring force to regulator control element 18 from one of the,translators, here diaphragm 45, lever 52 being pivoted for swingingabout an axis parallel to axis 19. A slider 53' for transferring forcefrom lever 52 to control element 18 is adjustable along the lengths ofmembers 18,. 52, so that the effective lever arms through which areoppositely exerted and compared, the forces exerted by diaphragms 4-5,46, may be inversely varied. Thereby the ratios of response in degreeangular movement of control element 18 to distances of lateralshift ofthe difierent web edges 25, 26, may be adjusted and equal ized, toovercome the noted unavoidable response differ ences' of systems 29, 42,45 and 30, 43,. 46. Diaphragms 45, 46 are connected respectively tolever 52 and to control element 18 by thrust links 54. I,

It will now be seen that, with ratio slider member 5-3.

so positioned that equal forces are oppositely exerted: on member 18while equal lengths of the detector re-- ceiver ports 33' are exposed tojet streams delivered from the nozzle slots 37, and with marginalportions of a web.

6* traveling through the detector throats 38, any departure of the webedges, from symmetrical spacing. fromthe preselected web center linepath, from which the detectors are symmetrically spaced, and whethercausedby lateral shift of the web asa whole or by variation in thewebaction will continue until the web center line has been registeredwith its preselected path, at which time the receiver port slots 38 willbe equally masked, resulting in return of member 18 to its neutralposition and termination, of relay operation.

I claim: 7

1. Meansv for detecting andindicating the lateral position of the centerline of a longitudinally traveling webthe lateral positions of the edgesof which may shift either incorresponding directions as a consequence oflateral movement of the web or relative to each other as a consequenceof varying web width, said means comprising a first we-b edge detectorarranged for sensing the lateral position of a first one of the edges ofsaid web and. developing a first signal the magnitude of which variescontinuously and proportionally with degree of change in the lateralposition of said first web edge, a second web edge detector arrangedlaterally opposite said first" detector' for sensing the lateralposition of the otheredge of said web and developing a second signal themagnitude of which varies continuously and proportionally with degree ofchange in the lateral-position of said other edge, and summarizer meanscoupled with both said detectors and arranged to'compare the magnitudesof said first and second signals andto produce a third signal themagnitude of which continuously and proportionally varies with thedifference between the magnitudes of said first and second signals. a

2. Means for detecting and indicating the lateral position of the centerline of a longitudinally traveling web the lateral positions of theedges of which may shift either in corresponding directions as aconsequence of lateral movement of the web, or relative to each other asa consequence of varying web width, said means comprising a pair offixed web edge lateral position detectors spaced apart across the pathof the web, each of said detectors being arranged to sense the positionof a different one of said web edges and to develop a signal themagnitude of which continuously and proportionally varieswith degree ofchange in the lateral position of the web edges the position of which itis arranged to sense, andsummarizer means coupled to both said detectorsand arranged to compare the magnitudes of said signals in senses suchthat changes in the magnitudes of the different signals corresponding toshifts of the different web edges in opposite directions are opposed toeach other and changes in their magnitudes corresponding to shifts ofboth web edges in the same direc-,

tion aid each other, and said summarizer means being arranged to producea final signal the magnitude of which continuously and proportionallyvaries with the difference between the magnitudes of the flIStIlZWO saidsignals. 3. Means according to claim 2, wherein said detectors are ofpneumatic type, arranged to produce signal pressures that comprise saidfirst and second signals, and wherein said summarizer means comprise anexpansible chamber assembly including movable wall structure subjectedto said signal pressures, and an output member movable by saidwallstructure to a position corresponding to the difference inmagnitudes of said signal pressures.

4. Means according to claim 2, wherein said detectors are of pneumatictype, arranged to produce signal pressures that comprise said first andsecond signals, and arranged to vary the magnitudes of the differentsaid signal pressures in the same senses in response to shift of therespective web edges in opposite directions and to vary the magnitudesof the different said pressures in opposite senses in response to shiftof the respective web edges in the same directions, and wherein saidsummarize means comprise an expansible chamber assembly includingmovable wall structure subjected to said signal pressures and an outputmember connected thereto and positionable thereby in correspondence tothe difference in magnitudes of said signal pressures.

5. Means according to claim 2, wherein said detectors are of pneumatictype, arranged to produce signal pressures that comprise said first andsecond signals, and

arranged to vary the magnitudes of the different saidsignal pressures inthe same senses in response to shift of the respective web edges inopposite directions and to vary the magnitudes of the different saidpressures in opposite senses in response to shift of the respective webedges in the same directions, and wherein said summarizer means comprisea pair of expansible chamber devices each connected with a ditferent oneof said detectors for exertion within it of the signal pressuredeveloped by that detector, each said device having a movable wallpartly enclosing its said chamber, a movable member, and a mechanicaltransmission system connecting said member to each said wall forpositioning the member in correspondence to the difference in magnitudesof the different said signal pressures.

6. Means according to claim 2, wherein said detectors are of pneumatictype, arranged to produce signal pressures that comprise said first andsecondsignals, and arranged to vary the magnitudes of the different saidsignal pressures in the same senses in responsp to shift of therespective web edges in opposite directions and to vary the magnitudesof the different said signal pressures inopposite senses in response toshift of the respective web edges in the same directions, and whereinsaid surnmarizer means comprise a pair of expansible chamber deviceseach having a chamber connected with a different one of said detectorsfor exertion in the chamber of the signal pressure developed by thatdetector, and a movable wall partly enclosing said chamber, said movablewalls ot the different expansible chamber devices being arranged inspaced opposition, a movable member positioned between said movablewalls, mechanical linkages connecting the diiferent said walls to saidmember for positioning the latter in correspondence to the difference inmagnitudes of said signal pressures, and at least one of said linkagesincluding an adjustable relative motion mechanism providing foradjustment to compensate differences in the characteristics of responsesof the respective expansible chamber devices toequal shifts of the saidrespective web edges.

7. In a system for delivering a longitudinally traveling web toapparatus for performing an operation thereon and including mechanismfor relatively shifting the apparatus and web in directions extendedtransverse to the latter; means for maintaining the center line of theweb in a preselected path that has a preselected transverse positionalrelation to the apparatus, comprising a pair of web edge positiondetectors disposed in fixed relation to said apparatus and spaced acrossthe web path in symmetrical spacing from said-center line path and indispositions for respectively detecting the lateral positions of thediiferent web edges, each said detector being arranged to develop adetector signal the magnitude of which varies continuously andproportionally in response to changes in the spacing from said centerline tudes indicative of different spacings of said web edges from saidcenter line path to accomplish relative shifting of said apparatus andweb in a sense to eliminate the difference in said spacings.

8. Means in a system for delivering a longitudinally traveling web toapparatus for performing an operation thereon and including mechanismfor relatively shifting the apparatus and web in directions transverseto the latter, and said mechanism having a control element that ismovable in opposite directions from a neutral position wherein saidmechanism is maintained idle, respectively to actuate said mechanism torelatively shift said weband apparatus in opposite directional senses;said means being arranged to maintain the center line of the web in adefinite path having a preselected transverse positional relation tosaid apparatus, and comprising a pair of web edge position detectorsdisposed in fixed positional relation to said apparatus and insymmetrical spacing relative to said center line path, the differentsaid detectors being disposed to sense the lateral positions of thedifferent edges of the web and each being arranged to develop a detectorsignal the magnitude of which varies continuously and proportionally incorrespondence to changes in spacing from said center line path of theWeb edge the position of which it detects, a translator device coupledto both said detectors, connected with said control element andresponsive to both said detector signals to maintain said element in itsneutral position while magnitudes of said signals correspond to equalspacings of the web edges from said center line path, and upon saidsignal magnitudes becoming indicative of difference in said spacings tomove said control element in the direction to actuate 9. Meansaceordingto claim 8-, wherein said detectors are arranged to develop fluidpsessure detector signals and said translator device comprises a forcebalance assembly having a pair of expansible chambers respectivelycoupled to the diiferent said detectors for developing forces ofmagnitudes corresponding to said signals, movable wall structure partlyenclosing said chambers, and linkage mechanically connecting saidmovable wall structure to said control element.

10. Means-according to claim 9, wherein said control element is elongateand pivoted for swinging movement, andsaid linkage includes anadjustable force-distance selecting connection betweensaid element andthe. wall structure enclosing one of said chambers.

ll. Means according to claim 8, wherein said detectors are arranged todevelop fluid pressure detector signals both of which vary in the sameone sense in-response to increase of spacings of the web edges from saidcenter line path and in the same opposite sense in response to decreasein said spacings, and said translator device comprises a pair ofexpansible chamber assemblies respectively coupled to the diiferentsaiddetectors for translating the different detector signals to forcesof corresponding magnitudes, and said means including linkage connecting the movable walls of said assemblies with said control elementfor opposite exertion thereon of the forces developed by the differentsaid assemblies.

12. Means according. to claim 8, wherein said detectors are arranged'todevelop fluid pressure detector signals both of which vary in the sameone sense in response to'increase of spacings of the diflferent webedges from said center line path and in the same opposite. senseinresponse to. decrease. in said spacings, said control elementcomprises a member that is pivoted for swinging, said translatorcomprises a pair of expansible motor assemblies respectively coupled tothe diifererit said detectors fortranslating said detector signals toforces of correspondingmagnitudes, said linkage comprises a link agemechanically connecting the-movable wall of one said assembly to saidcontrol element for exerting thereon and in one of its directions ofswing the force developed References Cited in-the file of this patentUNITED STATES PATENTS 2,539,131 Gundersen et a1. Jan. 23, 1951 2,666,639Frommer Ian. 19,. 1954 2,726,858 Cherigie Dec. 13, 1955 2,735,630Ziebolz Feb. 21, 1956

